Wine 101 / January 19, 2017

Grape to Glass: Bottling

After the winemaker feels like the wine is complete, it’s time to bottle the wine for distribution.

All wineries in New Zealand are required to use screw caps Screw caps are no longer a “cheap wine indicator” Natural cork is the most common choice for closures Natural cork lets in small amounts of oxygen called “micro-oxygenation”, an important part of long-term bottle aging New types of synthetic cork continue to enter the market Synthetic corks don’t deteriorate, nor do they have a tendency to leak
Wine ages in two different ways. Aerobically – that’s when it’s fermenting in the tank, completing the chemical changes that take it from grape juice to wine.  Wine also ages anaerobically. That’s the kind of aging that occurs after bottling the wine. The many tiny chemical changes that really develop the complex flavor and aroma of the wine happen in the bottle.

Everything depends on the winemaker’s expertise when it comes to knowing if the wine is ready for bottling. The winemaker makes sure that the wine is clear and free of sediment. Winemakers know that although aging can change the flavor of the wine, any problems that are put into the bottle will stay there permanently.

Bottle Shape

Bottle shape is determined by history and winemaker preference. Usually Cabernet Sauvignons are bottled in the traditional Bordeaux bottles. As well, you’ll often find Chardonnays in the sloped “shoulders” of the Burgundy bottle. But any shape will work for any wine.

For wine bottle color, winemakers generally choose green glass bottles for red wines. White wines are typically contained in clear bottles – long-term aging in clear bottles can brown the contents of the bottle. Since white wines are not usually aged for the same length of time as red wines, browning isn’t a consideration.

The process that wine goes through to get in the bottles is similar for other food products and drinks. Impressive to watch, bottles are filled and closed on a bottling line, where each bottle is filled, corked and labeled. A corking machine (also known as a corker) compresses the cork and pushes it into the neck of the wine bottle.

Winemakers have several choices for bottle enclosures. They can choose either screw cap, glass top or cork. And when it comes to cork, winemakers can choose to go with either composite cork or natural cork to close their bottles.

Screw Caps
Previously, screw caps were thought to be an indicator of cheap wine. Over the past few years, screw caps are gaining in popularity especially in New Zealand, where bottles must be closed with screw caps.


  • Less spoiled wine due to bad corks
  • Less potential for leakage
  • Convenience


  • Screw caps don’t allow for micro-oxygenation as a natural cork will.
  • Some very sensitive palates may pick up a flavor from the closure.

All in all, for short-term storage and aging, screw caps are fine.

Natural Cork
Natural cork is a crop – just like grapes. Since this is the most historical choice for closures, it’s the most common.


  • Natural cork lets in small amounts of oxygen. This is called “micro-oxygenation”, an important part of long-term bottle aging.


  • A defective cork can leave your wine “corked” (tasting like musty newspaper).
  • Leaks – natural cork is not completely airtight and can result in leaking

Natural corks have been proven to work over tens of thousands of years and are considered the traditional closure.

Composite/Synthetic Cork

Synthetic corks have gotten better since the 1990s when they were introduced.


  • Synthetic corks don’t deteriorate, nor do they have a tendency to leak.


  • Many synthetic corks do not allow for micro-oxygenation.

New types of synthetic cork continue to enter the market, broadening our options for wine closures.

Now that the wine is in bottles, it’s ready for storage or to drink. Have any questions about the bottling process? Put it in the comments!


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